In the Journal of Polymer Science: Polymer Letters Edition, Volume 16 of 1978, pages 607-614 G. N. Patel et al. describe polymers of certain alpha, omega diacetylene bis(butoxycarbonylmethyl urethanes) and analogous ethoxy compounds; which, unlike theretofore known polydiacetylenic compounds, are substantially soluble in certain common organic solvents. Such solutions are remarkable in showing dramatic color changes when a nonsolvent is added.